BQ27421-G1: bq27421G1D Learning fail

Hi Jerry

Firstly, you are using a dsg current that is very close to the c/10 threshold that disqualifies resistance updates. Secondly you are not hitting taper current conditions. You are stopping charge abruptly. Ensure you are tapering during charge and the FC flag gets set based on taper conditions.

thanks

Onyx

Why do you think learning failed. What is the criteria that you are using to determine learning failed.?

thanks

Onyx

Hi Jerry,

You might be using a wrong device for your cells. Have you ran our online tool to determine if the bq27421 is a good match for your chemistry?

thanks

Onyx

The log file from Learning Cycle-20190702.zip shows that Flags() BAT_DET is never set. The gauge will still report results but it didn't go through some initialization processes that are required for proper learning if it didn't detect a battery.

OpConfig is 0x35ED so BIE is 1. Please make sure that the BIN pin is pulled down. This is usually done with a thermistor (10k nominal resistance at room temperature) or a 10k resistor. TEMPS is 1 so this indicates that you don't use a thermistor but instead write the temperature to the gauge with your host uC. If you don't use a thermistor or 10k resistor on BIN and you don't want to use the battery detection feature, you can set BIE to 0 (OpConfig = 0x05ED) and then issue sub-command BAT_INSERT (0x000C).